Obviously I failed to track all my changes in that changeset, and especially
the move-and-modernize approach has fired back here - sorry, and thanks to
Ryan J Ollos for spotting this as well as the right place for the fix.

I took the chance to improve template format like I'd do for others later on.
That's bound to break msgid's for translation, but I'll need to do a message
extraction for other recent i18n-relevant changes anyway.

Nov 13, 2012:

Now EmailDistributor cares for the preferred format, that is configured per
user in the subscription db table, obsoleting related
'announcer_email_format_<realm>' entries stored in session_attribute db
table before.

While this is yet another regression, because this setting has been per target
(resource) realm before, in theory it could even be more fine-grained.
In fact, its possible to store the preferred format per subscriber insubscription. Only it is unified per transport for now, and I see no real
value in changing this, yet.

This fixes inappropriate alternative text display of non-ascii characters inHTML emails, that get sent out as multi-part message in MIME format.

This has been reported by g1itch, who did investigations and patch as well.
Works like a breeze, but this must have been much harder to fix than one would
expect at first glance onto this one-liner. It's a pleasure to follow your
footsteps, thanks a bunch.